Canceling the Gravity Gradient Phase Shift in Atom Interferometry
Canceling the Gravity Gradient Phase Shift in Atom Interferometry
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DOI：
10.1103/physrevlett.119.253201
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发表时间：
2017-12-19
影响因子：
8.6
通讯作者：
Tino, G. M.
中科院分区：
文献类型：
--
作者：
D'Amico, G.;Rosi, G.;Tino, G. M.
重力梯度是原子干涉测量高精度测量的主要障碍。将其影响控制到所需的稳定性和准确性，对自由落体原子云的相对定位提出了非常严格的要求，就像爱因斯坦等效原理的精确测试一样。我们展示了一种新方法，可以精确补偿拉曼脉冲原子干涉仪中重力梯度引入的影响。通过在中心 pi 脉冲期间改变拉曼激光器的频率，可以消除由重力梯度产生的初始位置和速度相关的相移。我们将该技术应用于沿垂直方向定位的同步干涉仪，并演示了一种测量局部重力梯度的新方法，该方法不需要精确了解原子云之间的相对位置。基于该方法，我们还提出了一种改进方案来确定牛顿引力常数G，使其相对不确定度达到10 ppm。
Gravity gradients represent a major obstacle in high-precision measurements by atom interferometry. Controlling their effects to the required stability and accuracy imposes very stringent requirements on the relative positioning of freely falling atomic clouds, as in the case of precise tests of Einstein's equivalence principle. We demonstrate a new method to exactly compensate the effects introduced by gravity gradients in a Raman-pulse atom interferometer. By shifting the frequency of the Raman lasers during the central pi pulse, it is possible to cancel the initial position- and velocity-dependent phase shift produced by gravity gradients. We apply this technique to simultaneous interferometers positioned along the vertical direction and demonstrate a new method for measuring local gravity gradients that does not require precise knowledge of the relative position between the atomic clouds. Based on this method, we also propose an improved scheme to determine the Newtonian gravitational constant G towards the 10 ppm relative uncertainty.